Of chicago



April 17, 1928. 1,666,163

P. A. CHAMBERLAIN RADIO CONDENSER Original Filed July 2, 1924 2 Sheets-Sheet l J3 llllllll April 17, 1928.

1,666,163 P. A. CHAMBERLAIN RADIO CONDENSER -0ri2inal Filed July 2, 1924 2 Sheets-Sheet 2 jfiae7dop Patented Apr; 17, 1928.

UNITED. STATES 1,666,163 PATENT OFFICE.

PAUL A. CHAMBERLAIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO MOHAWK CORPORA- TION OF ILLINOIS, OF CHICAGO, ILLINOIS, A CORPORATION 01' ILLINOIS.

BADIOCONDENSER.

- Original application filed July 2, 1924, Serial Nd. 723,617. Divided and this application filed January 22,

i 1926. Serial No. 82 934.

shown in Figure 1.

Figure 3 is an end view of the condenser This invention relates to improvements in multiple circuit controlling devices for radio apparatus, and more particularly to con densers adapted for use in multiple circuits and has for its principal object to provide an improved form of apparatus of the class described in which two or morecondensers each coupled in a separate circuit, as for instance, in successiveamplification. stages of radio receiving or sending set, may be 'well adjusted and the respective circuits balanced so as to afford simultaneous control of the circuits by manipulation of a single controlling member.

The present application is a division of application Serial No. 723,617, filed July 2, 1924, and relates particularly ,to features of construction of a multiple unit condenser and the means for insulating the stator units on the framethereof, regardless of whether balancing and shielding means are used, such asforms the subject matter of the claims in the application of which'this is a division.

The invention may best be understood by reference to the accompanying drawings, in which Figure 1 is a plancview of one form of condenser constructed in accordance with my invention.

Figure 2 is a side View of the condenser shown in Figure 1 with a part broken away to show one end of a shielding plate.

Figure 4 is a diagram showing a typical application of my invention to a portion of a radio frequency amplification apparatus; and

condenser construction. 4

Referring now to details shown on the drawings, Figures 1 to 3 illustrate a preferred form of condenser which may be used in carrying out my invention. This condenser comprises a frame consisting of metal end plates 10,-11, a pair of oppositely disposed connecting rods 12, 12 preferably threaded as shown and extending between the upper corners of the end plates 10, 11 and secured thereto by suitable means such as nuts 13, 13. A third connectingmember may connect the lower margins of the end plates centrally thereof, as shown herein this connecting member comprising a rod 16 secured Figure 5 is an enlarged diagram of the i to the end plates, by screws 17 17 The structure provided with a plurality of condenser units; in the form illustrated herein two of such condenser units 18 and 19 are shown, the first of which consists of a stator made up of a plurality of parallelly disposed plates 21, 21 spaced apart, and a rotor element made up of a plurality of plates 23, 23 interposed between adjacent stator plates. This condenser unit therefore comprises an air gap condenser of the usual construction, the stator plates'being substantially rectangular and the rotor plates being semi;circular in shape. The rotor plates are rotated so as to vary the capacity of theicondenser in the usual manner. The second unit 19 consists of a similar arrangement of stator plates 25 and rotor plates 26. In the form of condenser .shown in Figure 1, the stator plates 21, 21

suitable means, for instance, in Fig. 3 it will be seen that said plates are secured to pieces 34, 34 of conducting material, as for instance by welding, said block pieces 34 being mounted on the inner faces of the insulator blocks 3030 by means of screws 35-35. Terminals 3636 provide connection for the respective stator elements of condenser units 18 and 19. v

The rotor plates of condenser units 18 and 19 are mounted on the common shaft 40 in the usual manner, and the shaft has bearing in end plates 10 and 11 by any, suitable means, as, for instance, the bearing on plate 10 consists of a ball bearing 41 adjustable by a screw 42, while the opposite end of the shaft is provided with a split threaded hearing 43 adjustable by a nut 44 to vary the tension on,the shaft in the usual manner. The shaft is rotated by a prolongation 45 adapted to extend through a panel 46 in the usual manner for connection to a dial or similar manual adjusting device.

- The balancing and shielding means which may be utilized in connection with the inment (36.

posed therebetween and adjustable towardand away from the plates of the condenser units 18 and 19.

Referring now tothe use and operation of the condenser units just described, Figure 4 is a diagram showing a portion of a typical audion amplification apparatus in which the grid circuits of successive amplifieation stages are adapted to be tuned by means of shunt condensers, In the particular diagram illustrated, I have shown connections for portions of two stages of radio-frequency amplification. The grid circuit of the first stage includes the grid in an audion 61, a grid lead 6:2 to a secondary coil 63 of an input, transformer A grid return lead 64 connects said secondary coil to a negative filament lead 65 of audion fila- This negative lead connects with the negative side of A battery 67 and may also go to grounil 68. The plate circuit of the first audion includes the plate 70 and its lead 71 to primary 72 of transformer 73, thence by lead 74 to plus side of. A battery 67 through B battery 75. The filament 66. connects with plus A battery through rheostat 78 and leads 77 and The second audion 80 has similarly arranged grid and plate circuits, the grid circuit including the secondary coil 81 of the transformer 73, grid lead 82, and grid return 83. The plate circuit constitutes an output in the usual manner.

In the enlarged diagram in Figure 5, the construction of the condenser is' illustrated in greater detail showing diagrammatically the arrangement of the separate elements of the condenser units 18 and 19 including the rotor plates, stator plates and balancing plates.

1 claim as my invention:

1. A multiple variable condenser comprising, in combination, a pair of end plates, frame members interconnecting said end plates, a plurality of independent sets of journaled in said end plates, sets of rotor plates carried by said shaft and arranged to be interleaved between said sets of stator plates whereby the mutual capacity between said sets of platesmay be simultaneously varied by rotation of said central shaft.

2. A multiple variablecondenser comprising, in combination, a pair of end plates, frame members interconnecting said end plates, a plurality of independent sets of stator plates, conductive blocks supporting said stator plates in spaced relationship one from another, insulators interposed between said conduction blocks and said frame members whereby said stator plates may be posi tively supported in spaced relationship in a group independent from. another group of stator plates within said frame members, a central rotatable shaft journaled in said end plates, sets of rotor plates carried by said rotatable shaft and adapted to be inter-- leaved between said stator plates for varying the capacity between said sets of plates simultaneously upon rotation ofsaid central shaft. i

3. A multiple variable condenser comprising, in combination, a pair of end plates, frame members inter-connecting said end plates, a plurality of independent sets of stator plates, conductive blocks supporting said stator plates in spaced relationship one from another, a pair' of insulators interposed between said conductive blocks at opposite ends of said stator plates and said frame PAUL a. CHAMBERLAIN. 

